The preservation of food by dehydration is well known in the art. The early dehydration of food was typically carried out by placing the food product in an open container exposed to the air and to the sun. In more recent times, mechanical food dehydrators have been developed for use in the home. These food dehydrators typically include a plurality of shelves contained within a cabinet after which the food to be dried is placed. The dehydrator typically uses a motor driven fan to draw air through openings and circulate the air throughout the dehydrator. A heater is typically provided for heating the air before it is circulated by the fan, such as disclosed in U.S. Pat. No. 5,458,050 (Su).
A significant number of current food dehydrators locate the heater element and blower fan in the base. The heated air moves vertically through a series of perforated trays. The air is warmest and driest at the first tray, and becomes progressively cooler and more humid as it reaches the later trays. Therefore, the food on the trays closest to the hot air source get very dry, while that furthest from the source dries more slowly. Directing the heated air vertically through a series of trays results in uneven drying.
Locating the heating element and blower motor in the base also creates cleaning problems. These bases are typically not dishwasher safe. Additionally, the base can become contaminated with drippings that fall through the perforations in the trays. If meat products are dried, the grease drippings may create a fire hazard.
Many food dehydrators require the heated air to travel through various ducts before reaching the food. The ducts typically have multiple bends that result in velocity loss and heat dissipation before the heated air reaches the food. Consequently, more powerful heating elements and blower fans are typically used to compensate for the convoluted air flow paths through the dehydrator. Finally, most current dehydrators are large and bulky creating difficulties with use and storage in the home.